Wednesday, July 30, 2008

Andrew c. RevkinGlobal warming has felt like breaking news a few times in recent years. But the first big pulse of coverage and public attention came in 1988, when the Amazon Rainforest and Yellowstone were ablaze, a searing drought had farmers kicking dusty fields in frustration, and global temperatures had seen enough of a rise that a NASA climate expert, James Hansen, asserted before a Senate panel that statistics showed "the greenhouse effect has been detected and is changing our climate now."I thought it might be worth inviting you all to read and "annotate" (as we’ve done with a couple of climate speeches and polar bear decision recently) my cover story for Discover Magazine, reported through that hot year and published in the October 1988 edition. I asked the current management there if they’d post the original article. They liked the idea, but the article was so old that it wasn’t

even available in electronic form, so they had to type it up. Here’s the story, Melissa Lafsky of the magazine also did a brief e-mail interview with me, which is on their Reality base blog.

I’ll start by posting some relevant sections below and offering some reflections on how the story has stood the test of time. I’d enjoy seeing your reactions, pro or con.

I was not at the Senate Energy Committee hearing when Dr. Hansen testified. But I had been focused on climate and humans since 1984, when I began reporting what would end up being a long cover story for Science Digest magazine assessing nuclear winter, kind of the inverse potential human impact on climate (global cooling from a pall of smoke rising from incinerated cities). I went to Toronto one week after Dr. Hansen’s testimony to report from the first international "Conference on changing Atmosphere" — one of the seminal meetings building momentum toward the first report of the newborn InterGovernmental panel on climate change.

Nuclear winter, as I wrote in 1985, was more nuanced than the initial dramatic concept, morphing from a Page One post-apocalyptic apocalypse into a more subtle phenomenon, labeled "nuclear autumn" by Stephen H. Schneider. What is distinct about global warming is that the basics of 100-year-old theory have stood the test of time (more CO2 = warming world = less ice + higher seas and lots of climate change). Let’s dive into my old story to see what has, and has not, changed.After an opening section leading off with Dr. Hansen’s testimony:

Until this year, despite dire warnings from climatologists, the greenhouse effect has seemed somehow academic and far off. The idea behind it is simple: gases accumulating in the atmosphere as by-products of human industry and agriculture — carbon dioxide, mostly, but also methane, nitrous oxide, ozone, and chlorofluorocarbon — let in the sun’s warming rays but don’t let excess heat escape. As a result, mean global temperature has probably been rising for decades. But the rise has been so gradual that it has been masked by the much greater, and ordinary, year-to-year swings in world temperature.In my YouTube interview with Dr. Hansen, he discusses how the public remains attuned mainly to anomalies on short time scales — cold or warm — and misses the point that it is the long-term trend that he and other experts say will transform the planet, but at a pace invisible day to day.Not anymore, said Hansen. The 1980s have already seen the four hottest years on record, and 1988 is almost certain to be hotter still. Moreover, the seasonal, regional, and atmospheric patterns of rising temperatures — greater warming in winters than summers, greater warming at high latitudes than near the equator, and a cooling in the stratosphere while the lower atmosphere is warmer — jibe with what computer models predict should happen with greenhouse heating. And the warming comes at a time when, by rights, Earth should actually be cooler than normal. The sun’s radiance has dropped slightly since the 1970s, and dust thrown up by recent volcanic eruptions, especially that of Mexico’s El Chichon in 1982, should be keeping some sunlight from reaching the planet.What’s important here, and remains important, scientists say, is how the patterns of atmospheric and climatic change reveal the most about the involvement of greenhouse gases, not simply the change in global temperature.

Even though most climatologists think Hansen’s claims are premature, they agree that warming is on the way. Carbon dioxide levels are 25 percent higher now than they were in 1860, and the atmosphere’s burden of greenhouse gases is expected to keep growing. By the middle of the next century the resulting warming could boost global mean temperatures from three to nine degrees Fahrenheit. That doesn’t sound like much, but it equals the temperature rise since the end of the last ice age, and the consequences could be devastating. Weather patterns could shift, bringing drought to once fertile areas and heavy rains to fragile deserts that cannot handle them. As runoff from melting glaciers increases and warming seawater expands, sea level could rise as much as six feet, inundating low-lying coastal areas and islands. There would be dramatic disruptions of agriculture, water resources, fisheries, coastal activity, and energy use.

The range of possible warming from a particular rise in greenhouse gas concentrations is only a little narrower than it was back then. Again, this remains a risk-management challenge. As Dr. Hansen says in the video interview, climate is not something that we will "fix."

"Average climate will certainly get warmer," says Roger Revelle, an oceanographer and climatologist at the University of California at San Diego. "But what’s more serious is how many more hurricanes we’ll have, how many more droughts we’ll have, how many days above one hundred degrees." By Hansen’s reckoning, where Washington now averages one day a year over 100 degrees, it will average 12 such scorchers annually by the middle of the next century.At the time, the basic notion that warmer seawater would fuel hurricanes was young and untested. Most scientists projecting many more, and stronger storms, including Kerry Emanuel (quoted farther down in my 1988 story), have since shifted to more nuanced projections. Enough time has passed that Dr. Emanuel and some other researchers say intensification has already been seen. But the hurricane-climate connection remains an idea its formative stages.

Comparable climate shifts have happened before, but over tens of centuries, not tens of years. The unprecedented rapid change could accelerate the already high rate of species extinction as plants and animals fail to adapt quickly enough. For the first time in history humans are affecting the ecological balance of not just a region but the entire world, all at once. "We’re altering the environment far faster than we can possibly predict the consequences," says Stephen Schneider, a climate modeler at the National Center for Atmospheric Research in Boulder, Colorado. "This is bound to lead to some surprises."

The situation then remains similar today in that the worst-case outcomes from a greenhouse-warmed world are clearly possible, but with the probability hard to nail down. This is one reason the policy debate, essentially over how much to invest in a climate insurance policy, remains turbulent.A few themes that are central to climate discussions now were not part of the global warming story in 1988 — most notably the concept of thresholds and nonlinear "tipping points." The evidence that climate can shift abruptly had not yet emerged from ice cores in Greenland. All the curves looking forward were smooth.The rising role of developing countries was also described in the story, along with the looming challenge posed by the rise of China as an economic, and climatic, force:

In the end, the greatest obstacle facing those who are trying to slow the output of greenhouse gases is the fundamental and pervasive nature of the human activities that are causing the problem: deforestation, industrialization, energy production. As populations boom, productivity must keep up. And even as the developed nations of the world cut back on fossil fuel use, there will be no justifiable way to prevent the Third World from expanding its use of coal and oil. How can the developed countries expect that China, for example, which has plans to double its coal production in the next 15 years in order to spur development, will be willing or even able to change course?Overall, the story captured the same situation that scientists are still trying to describe now: a world poised for momentous changes that would be hard to reverse; the need for adaptation to inevitable changes and changes in energy choices to cut the chances of utter calamity; and the need to act in the face of uncertainty.

The piece culminated with a quote from Michael McElroy, a climate expert at Harvard, speaking at the Toronto climate conference. It could still be delivered today.Michael McElroy concluded, "If we choose to take on this challenge, it appears that we can slow the rate of change substantially, giving us time to develop mechanisms so that the cost to society and the damage to ecosystems can be minimized. We could alternatively close our eyes, hope for the best, and pay the cost when the bill comes due."

Again, I’d love to hear your thoughts on particular sections of the story. Point them out in your comment and I’ll post the relevant paragraph and link to your contribution.